This is a basic article for medical students and other non-radiologists
Chest x-rays are performed frequently in the assessment of a vast number of sick (and potentially very sick) patients.
A chest x-ray can be performed in the radiology department (usually with the patient standing up) or b...
Chlamydia pneumonia is a form of atypical pneumonia.
It is caused be the organism Chlamydophila pneumoniae (a species of Chlamydophila) which is an obligate intracellular bacterium that infects humans.
Non specific with overlap of features with pne...
The Chrispin-Norman score is used to provide a summative assessment of structural lung changes in patients with cystic fibrosis on plain chest radiographs.
It is useful to monitor disease progression or treatment response and can be used to compare between different patients in research studies...
There are many signs in radiology that are related to Christmas:
snowcap sign in avascular necrosis
in total anomalous pulmonary venous return
in pituitary macroadenomas
snowstorm appearance in complete hydatidiform and testicular microlithiasis
holly leaf sign in calcified pl...
Chronic aspiration pneumonia is a form of aspiration pneumonia according time of onset. This can include changes caused by microaspiration or macroaspiration of oro-gastric content through time.
This results from repeated passage of food material, gastro-oesophageal reflux content an...
Chronic beryllium lung disease (CBD) or sometimes just simply known as berylliosis refers to lung changes that can be seen with prolonged exposure to beryllium which is an alkaline earth metal that is used in many different industrial applications.
It is reported to occur in 2-5% ...
Chronic bilateral airspace opacification is a subset of the differential diagnosis for airspace opacification. An exhaustive list of all possible causes of chronic bilateral airspace opacities is long, but a useful framework is as follows:
granulomatosis with polyangi...
Chronic bronchitis (CB) is most commonly defined as the presence of productive cough for three months in two successive years in a patient in whom other causes of chronic cough, such as tuberculosis, lung cancer and heart failure, have been excluded. It can be an important pathological component...
Chronic cavitary pulmonary aspergillosis (CCPA) is considered the most common form of chronic pulmonary aspergillosis. In untreated cases, this may progress to chronic fibrosing pulmonary aspergillosis.
Chronic eosinophilic pneumonia (CEP) is an idiopathic condition characterised by the alveoli filling with an inflammatory, eosinophil-rich infiltrate. Classically on imaging, it appears as chronic consolidation with upper zone and peripheral predominance.
Most patients are middle ...
Chronic granulomatous disease (CGD) refers to heterogeneous group of inherited immune deficiency disorders characterised by the inability to destroy phagocyted catalase positive bacteria due to lack of NADPH oxidase which results in formation of granulomas in different tissues.
Pulmonary manifestations of chronic granulomatous disease can be seen approximately 80% of cases of chronic granulomatous disease, which is a disease characterised by multiple bacterial and fungal infections occurring as a result of a defect in the gene that encodes NADPH oxidase.
The most comm...
Chronic hypersensitivity pneumonitis (CHP) refers to hypersensitivity pneumonitis where there is radiological evidence of fibrosis and represents the end-stage of repeated or persistent pneumonitis 7.
High-resolution CT of the chest typically reveals indistinct centri...
Chronic interstitial pneumonitis is a broad descriptive term where an interstitial pneumonia has a prolonged course. It can arise of a range of aetiologies. The term does not usually imply a specific radiographic pattern and includes UIP, NSIP or other pattern. As a general rule there is little ...
Chronic lung allograft dysfunction (CLAD) is a clinical spirometric diagnosis characterised by an irreversible decline in the FEV1 of 20% or more relative to the highest post-transplant baseline representing one of the significant limitations in the survival of post-lung transplant patients. It ...
Chronic obstructive pulmonary disease (COPD) represents a spectrum of obstructive airway diseases. It includes two key components which are chronic bronchitis-small airways disease and emphysema.
The most common cause has historically been, and unfortunately continues to be, smok...
Chronic pulmonary aspergillosis (CPA) is a group of chronic aspergillosis found in non-immunocompromised patients with prior or current lung disease (e.g. chronic obstructive pulmonary disease, mycobacteriosis or conditions such as diabetes).
It can manifest as several forms 1.
Chronic pulmonary emboli are mainly a consequence of incomplete resolution of pulmonary thromboembolism.
vascular CT signs include
direct pulmonary artery signs
calcified thrombus - calcific pulmonary ...
Chronic suppurative lung disease (CSLD) refers to a group of conditions which includes:
primary ciliary dyskinesia
This term is usually used in the context of paediatric patients.
Chronic thromboembolic pulmonary hypertension (CTEPH) is a distinct subgroup of pulmonary hypertension that most frequently develops following massive or repeated pulmonary embolism.
The term CTEPH should be used for patients with chronic thromboembolic disease and pulmonary hypert...
Chronic unilateral airspace opacification is a subset of the differential diagnoses for airspace opacification. An exhaustive list of all possible causes of chronic unilateral airspace opacities is long, but a useful framework is as follows:
A chylothorax refers to the presence of chylous fluid in the pleural space often as a result of obstruction or disruption to the thoracic duct. It may be congenital or acquired.
Chylothoraces may present with variable pleural fluid appearance and biochemical characteristics; they are...
Cicatrisation atelectasis is a form of lung atelectasis which occurs as a result of scarring or fibrosis that reduces lung expansion. Common aetiologies include granulomatous disease, necrotising pneumonia and radiation fibrosis.
The term is closely related to cicatrisation collapse when an ent...
Circumflex aorta is a rare aortic arch anomaly caused by retroesophageal crossing of the aorta to the contralateral side. A vascular ring is formed when a ductus or ligamentum arteriosum contralateral to the aortic arch connects the descending aorta to the pulmonary artery.
A Clagett thoracotomy is a three stage procedure performed for treatment severe empyema and involves the resection of a posterolateral lower rib and the formation of an open window in the lateral aspect of the chest to allow continuous drainage and irrigation of the cavity with antibiotic soluti...
Clear cell tumours of the lung are rare benign pulmonary neoplasms that contain an abundant amount of glycogen. It is often classified under the spectrum of perivascular epithelioid cell tumours (PEComas).
Usually seen as a rounded, smooth-walled, and peripheral parenchym...
Coal workers' pneumoconiosis (CWP) is an occupational disease (type of pneumoconiosis) caused by exposure to coal dust free of silica (washed coal). Histologically, CWP is classified according to disease severity into simple (presence of coal macules) and complicated (with progressive massive fi...
Coarctation of the aorta (CoA) refers to a narrowing of the aortic lumen.
Coarctations account for between 5-8% of all congenital heart defects. They are more frequent in males, M:F ratio of ~2-3:1.
Varies accordingly to the degree of stenosis and the assoc...
Coccidioidomycosis refers to an infection caused by the dimorphic fungus Coccidioides spp, usually localised to the lungs. This disease is not to be confused with the similarly named paracoccidioidomycosis.
The most common forms of Coccidioides spp are Coccidioides immitis and Coc...
Coin lesion refers to a round or oval, well-circumscribed solitary pulmonary lesion. It is usually 1-5 cm in diameter and calcification may or may not be present 1,3. Typically but not always the patient is asymptomatic 1.
The differential diagnosis for such lesions is ...
The collar sign, also called the hourglass sign, is a helpful sign for diagnosis of diaphragmatic rupture on coronal or sagittal CT/ MR images and barium studies. It refers to a waist-like or collar-like appearance of herniated organs at the level of the diaphragm.
dependent viscera s...
Combined pulmonary fibrosis and emphysema (CPFE) are a possible new addition to a growing list of smoking-related lung disease characterised by the coexistence of usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) with emphysema in smokers.
The comet tail sign is a finding that can be seen on CT scans of the chest. It consists of a curvilinear opacity that extends from a subpleural "mass" toward the ipsilateral hilum. The comet tail sign is produced by the distortion of vessels and bronchi that lead to an adjacent area of round ate...
Common variable immunodeficiency (CVID) is a condition that is associated with an impaired immune system. It is considered the most common symptomatic primary immunodeficiency, and is characterised by recurrent respiratory tract infections.
The commonest presentation is t...
Pulmonary manifestations of common variable immunodeficiency can be variable. The respiratory system is one of the most commenly affected systems in common variable immunodeficiency.
Radiographic disease spectrum
bronchiectasis with interstitial lung disease (e.g. granulomatous-lymp...
Complete tracheal rings are a rare, isolated tracheal or tracheobronchial anomaly resulting from abnormal cartilage growth, forming a complete ring and often causing airway stenosis.
Clinically, it manifests as respiratory distress in infants or mild symptomatic airway co...
Computed tomography (CT) of the chest is a cross-sectional evaluation of the heart, airways, lungs, mediastinum, and associated bones and soft tissues.
Two key methods of image acquisition include:
standard CT with 5 mm slice thickness for mediastinum and gross evaluation of lungs
Mnemonics for conditions with a lower lobe predominance in chest radiology include:
C: collagen vascular disease
I: idiopathic pulmonary fibrosis
A: aspiration pneumonia
D: drugs; desquamative interstitial pneumonia
Congenital cardiovascular anomalies are relatively common, with an incidence of up to 1% if small muscular VSDs are included. As a group, there is a much greater frequency in syndromic infants and in those that are stillborn.
Broadly, congenital cardiovascular anomalies ...
Congenital cystic bronchiectasis is a rare entity, and as the name suggests is characterised by cystic bronchiectasis found in infancy 1. The term appears to have fallen out of favour, due to variable use in older literature. In most instances of congenital cystic bronchiectasis has what is now ...
With the advent of echocardiography, and cardiac CT and MRI, the role of chest x-rays in evaluating congenital heart disease has been largely been relegated to one of historical and academic interest, although they continue to crop up in radiology exams. In most instances a definite diagnosis ca...
Congenital high airways obstruction syndrome (CHAOS) refers to a rare, often lethal, congenital laryngotracheal condition and is primarily characterised by obstruction to the fetal upper airway.
CHAOS can be of three possible types 2:
complete laryngeal atresia without an oesophagea...
Congenital lobar overinflation (CLO), previously called congenital lobar emphysema, is a congenital lung abnormality that results in progressive overinflation of one or more lobes of a neonate's lung.
On imaging, it classically presents on chest radiographs as a hyperlucent lung segment with o...
Congenital pulmonary airway malformations (CPAM) are multicystic masses of segmental lung tissue with abnormal bronchial proliferation. CPAMs are considered part of the spectrum of bronchopulmonary foregut malformations.
Until recently they were described as congenital cystic adeno...
Congenital pulmonary lymphangiectasia refers to congenital dilatation of the lymphatic system.
It typically presents in infancy. It may be isolated to lung or may be part of a generalised lymphangiectasia.
Congenital pulmonary venolobar syndrome is a condition comprised of a rare group of cardiac and pulmonary congenital abnormalities occurring variably in combination. The abnormalities include:
anomalous pulmonary venous drainage
particularly scimitar syndrome with hypogenic right lung
Congenital tracheomalacia refers to a diverse group of conditions which result in a dilated trachea with increased compliance. Causes include:
cystic fibrosis: seen in up to 69% of patients 4
Mounier-Kuhn syndrome: idiopathic or associated with
Ehlers-Danlos syndrome (in adults)
cutis laxa (...
Congenital tracheo-oesophageal fistula is a congenital pathological communication between the trachea and oesophagus.
Tracheo-oesophageal fistula and oesophageal atresia have a combined incidence of approximately 1 in 3500 live births 1-3,5. There is only a minimal hereditary/ge...
Congestive cardiac failure (CCF), also known as congestive heart failure (CHF), refers to the clinical syndrome caused by inherited or acquired abnormalities of heart structure and function, causing a constellation of symptoms and signs that lead to decreased quality and quantity of life.
Constrictive pericarditis (or perhaps better termed pericardial constriction) is a type of pericarditis which leads to diastolic dysfunction and potentially symptoms of right heart failure.
No single demographic is affected as there are numerous causes of constrictive pericarditi...
The continuous diaphragm sign is a chest radiograph sign of pneumomediastinum or pneumopericardium if lucency is above the diaphragm, or of pneumoperitoneum if lucency is below the diaphragm.
Normally the central portion of the diaphragm is not discretely visualised on chest radiographs as it ...
This is a basic article for medical students and other non-radiologists
COPD (chronic obstructive pulmonary disease) is defined as a condition characterised by persistent air flow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways...
The coracoclavicular joint is a normal variant of the pectoral girdle, where the conoid tubercle of the clavicle appears enlarged or elongated, with a flattened inferior surface where it approximates the coracoid process of the scapula to form an articulation.
More common in Asia...
Cor pulmonale is defined as a failure of the structure and function of the right ventricle in the absence of left ventricular dysfunction. It is caused by an underlying primary disorder of the respiratory system. It has a generally chronic and slowly progressive course, although acute onset or w...
Correct chest radiograph terminology is very helpful when describing pathology. It is especially important when describing findings to colleagues (radiologist or not), who may not be able to see the image in front of them, e.g. over the phone, or when describing an image in a radiology exam.
The costal cartilages form part of the thoracic cage and anterior chest wall. There are 10 costal cartilages, one for rib 1-10, with each of which forms a costochondral joint. Costal cartilages 1-7 articulate with the sternum at sternocostal joints, and costal cartilages 8-10 are attached to eac...
Costal cartilage fractures are fractures of the cartilage connecting the ribs anteriorly to the sternum.
There is little published data on costal cartilage fractures. Most reported cases are in males and resulted from blunt trauma or a fall 1,2.
In young ch...
The costal hook sign is a chest x-ray feature seen in some cases of flail chest. It represents the rotation of a fractured rib along its long axis, something that is only possible if a second fracture is present along its length, even if the second fracture is not visible 1.
The costocervical trunk is one of the branches of the second part of the subclavian artery. It arises from the posterior wall of the subclavian artery, posterior or medial to the anterior scalene muscle and courses posterosuperiorly across the suprapleural membrane where it divides into 2 branc...
The costochondral joints are the joints between each rib and its costal cartilage. They are primary cartilaginous joints. These joints represent the demarcation of the unossified and ossified part of the rib 1. The joint is held together by periosteum, with the lateral aspect of the costal ca...
The costoclavicular ligament or rhomboid ligament is the major stabilising factor of the sternoclavicular joint.
The costoclavicular ligament binds the inferior medial clavicle (via the rhomboid fossa) to the first costal cartilage and adjacent end of the first rib. It is compose...
The costoclavicular space is the anterior portion of the superior thoracic aperture, between the clavicle and first rib. The subclavian vessels and brachial plexus pass though the space related to the scalene muscles. Proximally, the plexus passes through the interscalene space, and distally thr...
The costovertebral joint is an articulation between the ribs and the vertebral column.
The ribs articulate with the thoracic vertebrae via two distinctly different joints:
costovertebral joint - articulation between the head of the rib and the vertebral body
The costoxiphoid ligaments, also known as the chondroxiphoid ligaments, are inconstant fibrous structures joining the anterior and posterior surfaces of the xiphoid to the respective surfaces of the adjacent seventh and, occasionally, sixth costal cartilages.
Crack lung is a term used to describe one of the respiratory complications of smoked crack cocaine.
Patients present with sympathetic hyperactivity such as tachycardia, hypertension, dilated pupils, and chest pain, productive cough, dyspnoea, and hypoxaemia along with fev...
Crazy paving refers to the appearance of ground-glass opacity with superimposed interlobular septal thickening and intralobular septal thickening, seen on chest HRCT. It is a non-specific finding that can be seen in a number of conditions.
Croup, also called acute laryngotracheobronchitis is due to viral infection of the upper airway by parainfluenza virus or respiratory syncytial virus (RSV).
On imaging, although not required for the diagnosis, it classically presents with a narrowing of the subglottic airway and ballooning of t...
Crow feet sign is a characteristic, but uncommon, feature seen in round atelectasis.
On CT, this is seen as linear bands radiating from a mass into adjacent lung tissue resembling the feet of a crow. This sign should not be confused with fibrotic changes occurring in the lung.
Cryptococcosis is a fungal infection caused by Cryptococcus neoformans, a globally distributed fungus that is commonly found in soil, especially that containing pigeon and avian droppings. Infection is acquired by inhaling spores of fungus.
Occurs worldwide without any defined en...
Cryptogenic fibrosing alveolitis (CFA) is a fibrosing lung disease that is characterised by inflammation and fibrosis of the alveoli and interstitium of the lungs, favouring the subpleural and basal regions.
There is some overlap in definition with the term idiopathic pulmonary fibrosis 1.
Cryptogenic organising pneumonia (COP) is a disease of unknown aetiology characterised on imaging by multifocal ground glass opacifications and/or consolidation. A wide variety of infectious as well as noninfectious causes may result in a similar histologic pattern.
The CT angiogram sign refers to vessels appearing prominent during a contrast enhanced CT as they traverse an airless low attenuation portion of consolidated lung. Although initially thought to be specific for bronchoalveolar carcinoma, it has now been recognised as a generic appearance provided...
This is a basic article for medical students and other non-radiologists
Chest CT is a computed tomography examination of the thoracic cavity performed for a variety of reasons, from suspected cancer to penetrating chest trauma.
A CT chest can be performed with or without IV contrast and when I...
CT guided thoracic biopsy is usually performed for the diagnosis of suspicious lung, pleural or mediastinal lesions. It can be performed as an outpatient where patient monitoring and complications support are available. A small percentage of lung and pleural biopsies may be performed under ultr...
CT polytrauma/multitrauma, also called trauma CT, whole body CT (WBCT) or panscan, is an increasingly used investigation in patients with multiple injuries sustained after significant trauma.
Clinical assessment and mechanism of injury may underestimate injury severity by 30% 8. There is some e...
Currarino-Silverman syndrome, also known as pectus carinatum type 2 deformity, is a rare disorder in which the patient has a high carinate chest deformity due to a premature fusion of the manubriosternal joint and sternal ossification centres. Congenital heart diseases have been described in mor...
This is a basic article for medical students and other non-radiologists
Chest x-ray CVC (central venous catheter) position should be assessed following initial placement and on subsequent radiographs.
This is a summary article; for a more in-depth reference article see centr...
A number of entities can present as cyanotic congenital heart disease. These can be divided into those with increased or decreased pulmonary vascularity (pulmonary plethora):
increased pulmonary vascularity
total anomalous pulmonary venous return (TAPVR) (types I and II)
transposition of the ...
Cylindrical bronchiectasis (or tubular bronchiectasis) is the most commonly identified morphologic type of bronchiectasis where there is smooth uniform enlargement of bronchi with loss of the normal distal tapering of the airways but without focal outpouchings or tortuosity.
A cyst is an abnormal fluid-filled structure which is lined by epithelium; with one exception: lung cysts contain gas, not fluid. By contradistinction, a pseudocyst lacks an epithelial lining and instead has a vascular and fibrotic capsule.
Cysts are extremely common and found in most organs. E...
Cystic bronchiectasis is one of the less common morphological forms of bronchiectasis. It is characterised by saccular dilatation of bronchi that extend to the pleural surfaces. When aggregated these may give a "bunch of grapes" like appearance. It may be present on its own or may be occur in co...
Cystic fibrosis (CF) is an autosomal recessive genetic disease that affects the exocrine function of the lungs, liver, pancreas, and small bowel resulting in progressive disability and multi-system failure. This article is a general discussion of the disease. Each organ system will be discussed ...
Pulmonary manifestations of cystic fibrosis are some of the best known in cystic fibrosis (CF). This is partly because the lungs are often severely affected and the cause of significant morbidity and mortality.
For general discussion of cystic fibrosis, and a discussion of its other manifestat...
Cystic hygroma, also known as cystic or nuchal lymphangioma, refers to the cystic variety of congenital lymphangioma which, most commonly, occur in the cervicofacial regions, particularly at the posterior cervical triangle.
They usually occur in the fetal/infantile and paediatri...
Cystic lung disease is an umbrella term used to group the conditions coursing with multiple lung cysts.
A lung cyst is a gas-filled structure with perceptible wall typically 1 mm in thickness but can be up to 4 mm. The diameter of a lung cyst is usually <1 cm. By conventional defini...
Cystic lesions in paediatric patients are usually congenital lesions and, as such, can be seen antenatally and following delivery.
These congenital lesions are predominantly covered by the overarching diagnosis of bronchopulmonary foregut malformation. This is ...
The differential diagnosis for cystic masses of the mediastinum include:
oesophageal duplication cyst
cystic teratoma of mediastinum
cystic degeneration of an intrathoracic tumour
Cystic or necrotic appearing lymph nodes can be caused by a number of infectious, inflammatory or malignant conditions:
squamous cell carcinoma metastases
plasmacytoid T-cell leukemia
acute myeloid leukemia
herpes simplex lymphadenit...
Cystic pulmonary metastases are atypical morphological form on pulmonary metastases where lesions manifest as distinct cystic lesions. It is slightly different form the term cavitating pulmonary metastases in that the lesions are extremely thin walled.
It has been reported with many ...
A cystic retroperitoneal lesion can carry a relatively broad differenital which includes:
retroperitoneal cystic lymphangioma
retroperitoneal mucinous cystadenoma
retroperitoneal cystic teratoma
retroperitoenal cystic mesothelioma
pseudomyxoma retroperitonei with cystic change
Cytomegalovirus (CMV) pneumonia is a type of viral pneumonitis and occurs due infection with cytomegalovirus (CMV), which is a member of the Herpetoviridae family.
CMV infection is particularly important in those who are immunocompromised (e.g. those with AIDS / allogenic bone mar...
The dark bronchus sign is the appearance of a relatively darker bronchus as compared to adjacent ground glass opacity. If the ground glass opacity progresses to consolidation, air bronchograms will be visualised.
This sign is useful to identify diffuse ground glass opacity on HRCT chest in cas...